Catalyst for producing polybutylene succinate or copolyester thereof, and preparing mehtods of the catalyst

ABSTRACT

The present invention provides a catalyst used in the production of PBS or its copolyesters and the preparation method thereof. The method comprises the following steps: (1) adding titanium alkoxide, silicon alkoxide, dihydric alcohol and metal co-catalyst into the solvent and conducting the reaction at a temperature of about 80° C. to 180° C., then removing the unreacted materials and small molecular products in the reaction system; (2) adding complexing agent into the reaction system, then collecting catalyst from the products obtained in this step. Moreover, the method may comprises steps of: (1) adding titanium alkoxide, dihydric alcohol and metal co-catalyst into the solvent and conducting the reaction at a temperature of about 80° C. to 180° C., then removing the unreacted materials and small molecular products in the reaction system; (2) adding silicon alkoxide and complexing agent into the reaction system, then collecting catalyst from the products obtained in this step. The catalyst in the present invention has higher activity and thus the catalyst additional amount is reduced which will improve the quality of the products. Moreover, the catalyst in the present invention could be used alone in the production of PBS or its copolyester without the need for other materials and it won&#39;t react with water and thus could be stored for a long time. In sum, the catalyst in the present invention has a broad prospect in industrial application.

FIELD OF THE INVENTION

The present invention relates to a catalyst used in the production ofPBS or its copolyesters and the preparation method thereof.

BACKGROUND OF THE INVENTION

Aliphatic polyesters has aroused wide attention and research fromdomestic and foreign scholars because of their great biodegradable andenvironmentally non-persistent properties. Aliphatic polyesters and inparticular poly (butylene succinate) (PBS) even have additionaladvantage features, such as good mechanical and processing properties.Therefore, PBS, which has enormous application prospect, becomes thefocus of attention in industry recently.

Previous attempts at the production of PBS or its copolyesters aregenerally fall into two kinds of production processes, chain extendingprocess and direct polycondensation process. In the chain extendingprocess, chain extender is added into the reaction system to react withthe organic groups of the polyesters in order to increase molecularweight. In general, the chain extenders mainly used are isocyanidealkoxides which are poisonous compounds and can't be used infood-related field. Because of the above property, the application ofPBS or its copolyesters has been limited. Compared with chain extendingprocess, the manufacture process and equipment of the directpolycondensation process are almost the same, however, there is no suchpoison chain extenders required in direct polycondensation process.Therefore, direct polycondensation process will become the most popularmanufacture method for PBS or its copolyesters in the future.

In the direct polycondensation process used to produce PBS or itscopolyesters, the polycondensation catalyst, such as titanium-basedcatalyst or the mixture of titanium-based catalyst and other metalcatalyst, is added into the reaction system. Chinese Patent application,CN 1424339 discloses a catalyst mixture comprising stannic oxide,antimony trioxide, cadmium acetate and titanium alkoxides. Moreover,Chinese Patent application, CN 1861660A discloses a catalyst mixturecomprising tetra-n-butyl titanate, tetra-isopropyl titanate, antimonytrioxide and tetra-n-butyl germinate. In practical manufacture process,titanate-based catalyst alone can't satisfy production requirements.Therefore, other compounds must be added into titanate catalyst to forma catalyst complex.

In light of the above, the catalyst system in prior art has followingdisadvantages such as: (1) The traditional catalyst has low activity andthus the additional amount of catalyst is very high which affects thequality of the products. For the traditional titanium alkoxides-basedcatalyst, additional amount of active ingredient (titanium) usually morethan 500 ppm (that is, 500×10⁻⁶ gTi/gPBS, similarly hereinafter),measured by weight of PBS. Sometimes the additional amount is evenhigher than 700 ppm. Such high catalyst amount could result in many sidereactions and it may also increase the melt flow rate of the products,decrease its mechanical properties and turn the products a dark yellowcolor. (2) The catalyst in prior art is not convenient for practicalmanufacture use because titanium alkoxides would easily causeprecipitation while contacting with water. However, during PBS synthesisprocedure, because the product in esterification procedure is water,titanium alkoxides could be added only after the esterificationprocedure. On the other hand, the catalyst in prior art is composed ofseveral other ingredients, the technicians must prepare for eachcomponents according to its proportion which is a complex procedurecomparing with the single-component catalyst.

SUMMARY OF THE INVENTION

The present invention provides a catalyst used in the production of PBSor its copolyesters and the preparation method thereof.

Consistent with one preferable embodiment of the present invention, amanufacturing method of the catalyst used in the production of PBS orits copolyesters is provided. The method comprises steps of:

(1) adding titanium alkoxide, silicon alkoxide, dihydric alcohol andmetal co-catalyst into the solvent and conducting the reaction at atemperature of about 80° C. to 180° C., more preferably 85° C. to 160°C., for 0.5 hour to 2.5 hours;(2) removing the unreacted materials and small molecular products in thereaction system obtained in step (1);(3) adding complexing agent into the reaction system obtained in step(2) and conducting the reaction at a temperature of about 80° C. to 180°C., more preferably 85° C. to 160° C., for 0.5 hour to 2.5 hours;(4) removing small molecular products in the reaction system obtained instep (3) and then catalyst could be obtained.

Consistent with another preferable embodiment of the present invention,a manufacturing method of the catalyst used in the production of PBS orits copolyesters is provided. The method comprises steps of:

(1) adding titanium alkoxide, dihydric alcohol and metal co-catalystinto the solvent and conducting the reaction at a temperature of about80° C. to 180° C., more preferably 85° C. to 160° C., for 0.5 hour to2.5 hours;(2) removing the unreacted materials and small molecular products in thereaction system obtained in step (1);(3) adding silicon alkoxide and complexing agent into the reactionsystem obtained in step (2) and conducting the reaction at a temperatureof about 80° C. to 180° C., more preferably 85° C. to 160° C., for 0.5hour to 2.5 hours;(4) removing small molecular products in the reaction system obtained instep (3) and then catalyst could be obtained.

The method used for removing the unreacted materials or small molecularproducts in the reaction system could adopt any conventional methodsknown by those skilled in the art, such as distillation or rectificationmethod, and any other methods which could be adopted by the skilled inthe art.

Preferably, said titanium alkoxide is selected from the group comprisingtetra-n-butyl titanate, tetra-isopropyl titanate and the mixturethereof.

Preferably, said silicon alkoxide is selected from the group comprisingmethyl silicate, ethyl silicate and the mixture thereof.

Surprisingly, the metal co-catalyst and complexing agent both have greatinfluence on catalyst activity and the choices on the catalysts.

Preferably, the said metal co-catalyst is selected from the acetates oralkoxides of Group IIA, IIIA, IIB or VIIIB metals, or any mixturethereof. More preferably, the said metal co-catalyst is selected fromthe group comprising zinc acetate, aluminium isopropoxide, calciumacetate, magnesium acetate, manganese acetate and any mixture thereof.

The said dihydric alcohol is selected from the group comprising1,4-butanediol, ethanediol, 1,3-propanediol, 2-methyl-2,4-pentadiol,1,5-pentanediol, 1,6-hexanediol and any mixture thereof.

Preferably, the said complexing agent comprises phosphate ester andhydroxyl carboxylic acids.

More preferably, the said phosphate ester is selected from the groupcomprising trimethyl phosphate, trimethyl phosphite, triethyl phosphate,triethyl phosphite and any mixture thereof.

More preferably, the said hydroxyl carboxylic acids is selected from thegroup comprising citric acid, tartaric acid, lactic acid and any mixturethereof.

Preferably, the said solvent is selected from the group comprisingethanol, n-butanol, isopropanol and any mixture thereof.

Preferably, the molar ratio of titanium atom and dihydric alcohol isranging from 1:5 to 1:30, more preferably ranging from 1:20 to 1:30.

Preferably, the molar ratio of titanium atom and the metal co-catalystis ranging from 1:0.05 to 1:2, more preferably ranging from 1:0.05 to1:0.5.

Preferably, the molar ratio of titanium atom and hydroxyl carboxylicacids is ranging from 1:0.5 to 1:2, more preferably ranging from 1:0.5to 1:1.5.

Preferably, the molar ratio of titanium atom and silicon atom is rangingfrom 1:0.01 to 1:2, more preferably ranging from 1:0.05 to 1:1.

Preferably, the molar ratio of titanium atom and phosphorus atoms isranging from 1:0.01 to 1:2, more preferably ranging from 1:0.01 to1:1.5.

Preferably, the molar ratio of titanium atom and the solvent is rangingfrom 1:5 to 1:50, more preferably ranging from 1:5 to 1:30.

The catalyst prepared according to the above methods could be used inthe production of PBS or its copolyester. During the preparation for PBSor its copolyester adopting succinic acid and 1,4-butanediol as the mainraw monomer materials, the above-mentioned catalyst could be addeddirectly into the reaction system or be added into the reaction systemafter being diluted with 1,4-butanediol. Moreover, the catalyst alsocould be added into the reaction system before the esterificationreaction, or be added into the reaction system after the esterificationreaction and before the start of the prepolycondensation.

The amount of catalyst added could be determined by the weight oftitanium atoms it contains, and the weight ratio of titanium atomscontained in the catalyst and total weight of PBS or its copolyester isranging from 80×10^(−6:)1˜200×10⁻⁶:1.

Preferably, the amount of catalyst could be determined by the weight oftitanium atoms it contained, and the weight ratio of titanium atomscontained in the catalyst and total weight of PBS or its copolyester isranging from 100×10⁻⁶:1˜150×10⁻⁶:1.

Compared with the traditional titanium alkoxides catalyst, the catalystcontaining metal co-catalyst in the present invention, which is preparedusing complexation technology, has the following advantages. Firstly,the catalyst in the present invention has higher activity and thus thecatalyst additional amount is reduced which will improve the quality ofthe products. Secondly, the catalyst in the present invention could beused alone in the production of PBS or its copolyester without the needfor other materials. Therefore, there is no need for additionalpreparation step as in the traditional preparation method. Thirdly, thecatalyst in the present invention will not react with water and it thuscould be added into the reaction system before the esterificationreaction, or after the esterification reaction and before the start ofthe prepolycondensation. In addition, the catalyst in the presentinvention could be stored for a long time. In sum, the catalyst in thepresent invention has a broad prospect in industrial application.

DETAIL DESCRIPTION OF THE INVENTION

The present disclosure is further explained in detail according to theaccompanying embodiments. The above description of the detailedembodiments are only to illustrate the preferred implementationaccording to the present invention, and it is not to limit the scope ofthe present invention, Accordingly, all modifications and variationscompleted by those with ordinary skill in the art should fall within thescope of present invention defined by the appended claims.

In the following embodiments, the melt mass-flow rate of PBS is measuredaccording to the determination method in “GB/T 3682-2000 Determinationof the melt mass-flow rate (MFR) and the melt volume-flow rate (MVR) ofthermoplastics”. The color of PBS is estimated using L, a, b-colorsystem as assessment baseline. In this L, a, b-color system, “L” meansluminance factor, “a” and “b” mean color measurement numbers. The “b”,which is used to estimate yellow-blue balance, is a significantevaluation number for the color of polyesters. A lower “b” value is asign of a better color.

The First Embodiment

Consistent with this embodiment, the manufacturing method of thecatalyst used in the production of PBS or its copolyesters comprisessteps of:(1) add 50 g of 1,4-butanediol (0.55 mol) into a 250 ml flask which isequipped with propeller and condensing unit, then add 1.73 g of calciumacetate (0.0098 mol) into the flask,(2) after that, add 29 g of tetra-n-butyl titanate (0.0852 mol) and31.51 g of ethanol (0.685 mol) into the flask, then conduct the reactionat a temperature of 80° C. for 2.5 hours,(3) remove small molecular products in the reaction system obtained instep (2) by dilution,(4) add 2.04 g of tetraethoxysilane (0.0098 mol) and 8.22 g of tartaricacid (0.0548 mol) into the reaction system in step (3) and conduct thereaction at a temperature at a temperature of 80° C. for 2.5 hours;(5) remove small molecular products in the reaction system obtained instep (4) by dilution and then catalyst in liquid state which contains5.12% of titanium by weight could be obtained.

The Second Embodiment

Consistent with this embodiment, the manufacturing method of thecatalyst used in the production of PBS or its copolyesters comprisessteps of:(1) add 50 g of 1,4-butanediol (0.55 mol) into a 250 ml flask which isequipped with propeller and condensing unit, then add 2.4 g of manganeseacetate (0.0098 mol) into the flask,(2) after that, add 19.44 g of tetra-isopropyl titanate (0.0685 mol) and31.51 g of ethanol (0.685 mol) into the flask, then conduct the reactionat a temperature of 110° C. for 0.5 hours,(3) remove small molecular products in the reaction system obtained instep (2) by dilution,(4) add 1.02 g of tetraethoxysilane (0.0049 mol) and 12.76 g oftrimethyl phosphite (0.1028 mol) into the reaction system in step (3)and conduct the reaction at a temperature at a temperature of 110° C.for 0.5 hours;(5) remove small molecular products in the reaction system obtained instep (4) by dilution and then catalyst in fluid state which contains4.14% of titanium by weight could be obtained.

The Third Embodiment

Consistent with this embodiment, the manufacturing method of thecatalyst used in the production of PBS or its copolyesters comprisessteps of:(1) add 50 g of 1,4-butanediol (0.55 mol) into a 250 ml flask which isequipped with propeller and condensing unit, then add 2.2 g of zincacetate (0.01 mol) into the flask,(2) after that, add 22.80 g of tetra-n-butyl titanate (0.067 mol) and92.46 g of ethanol (2.01 mol) into the flask, then conduct the reactionat a temperature of 180° C. for 1 hour,(3) remove small molecular products in the reaction system obtained instep (2) by dilution,(4) add 8.41 g of citric acid (0.04 mol), 5.10 g of tartaric acid (0.034mol), 2.08 g of tetraethoxysilane (0.01 mol) and 6.74 g of triethylphosphate (0.037 mol) into the reaction system in step (3) and conductthe reaction at a temperature at a temperature of 180° C. for 1 hour;(5) remove small molecular products in the reaction system obtained instep (4) by dilution and then catalyst in fluid state which contains4.02% of titanium by weight could be obtained.

The Fourth Embodiment

Consistent with this embodiment, the manufacturing method of thecatalyst used in the production of PBS or its copolyesters comprisessteps of:(1) add 100 g of 1,4-butanediol (1.11 mol) into a 250 ml flask which isequipped with propeller and condensing unit, then add 3.29 g of zincacetate (0.015 mol) into the flask,(2) after that, add 10.21 g of tetra-n-butyl titanate (0.03 mol), 8.517g of tetra-isopropyl titanate (0.03 mol), 3.12 g of tetraethoxysilane(0.015 mol) and 46 g of ethanol (1 mol) into the flask, then conduct thereaction at a temperature of 100° C. for 1 hour,(3) remove small molecular products in the reaction system obtained instep (2) by dilution,(4) add 9.05 g of lactic acid (0.105 mol) and 14.22 g of trimethylphosphate (0.1 mol) into the reaction system in step (3) and conduct thereaction at a temperature at a temperature of 150° C. for 1.2 hours;(5) remove small molecular products in the reaction system obtained instep (4) by dilution and then catalyst in fluid state which contains2.01% of titanium by weight could be obtained.

The Fifth Embodiment

Consistent with this embodiment, the manufacturing method of thecatalyst used in the production of PBS or its copolyesters comprisessteps of:(1) add 50 g of 1,4-butanediol (0.55 mol) into a 250 ml flask which isequipped with propeller and condensing unit, then add 3.22 g ofmagnesium acetate (0.015 mol) and 1.02 g of aluminium isopropoxide(0.005 mol) into the flask,(2) after that, add 22.80 g of tetra-n-butyl titanate (0.067 mol), 3.12g of tetraethoxysilane (0.015 mol) and 46 g of ethanol (1 mol) into theflask, then conduct the reaction at a temperature of 80° C. for 2.5hours,(3) remove small molecular products in the reaction system obtained instep (2) by dilution,(4) add 10.06 g of tartaric acid (0.067 mol) and 18.22 g of triethylphosphate (0.1 mol) into the reaction system in step (3) and conduct thereaction at a temperature at a temperature of 80° C. for 1.2 hours;(5) remove small molecular products in the reaction system obtained instep (4) by dilution and then catalyst in fluid state which contains3.24% of titanium by weight could be obtained.

The Sixth Embodiment

Consistent with this embodiment, the manufacturing method of thecatalyst used in the production of PBS or its copolyesters comprisessteps of:(1) add 50 g of 1,4-butanediol (0.55 mol) into a 250 ml flask which isequipped with propeller and condensing unit, then add 3.29 g of zincacetate (0.015 mol) and 1.76 g of calcium acetate (0.01 mol) into theflask,(2) after that, add 22.80 g of tetra-n-butyl titanate (0.067 mol) and 46g of ethanol (1 mol) into the flask, then conduct the reaction at atemperature of 180° C. for 1.8 hours,(3) remove small molecular products in the reaction system obtained instep (2) by dilution,(4) add 7.04 g of citric acid (0.034 mol), 2.28 g of methyl silicate(0.015 mol) and 14.22 g of triethyl phosphate (0.1 mol) into thereaction system in step (3) and conduct the reaction at a temperature ata temperature of 120° C. for 2 hours;(5) remove small molecular products in the reaction system obtained instep (4) by dilution and then catalyst in fluid state which contains3.49% of titanium by weight could be obtained.

The Seventh Embodiment

Consistent with this embodiment, the manufacturing method of thecatalyst used in the production of PBS or its copolyesters comprisessteps of:(1) add 50 g of 1,4-butanediol (0.55 mol), 2.04 g of aluminiumisopropoxide (0.01 mol) and 2.45 g of manganese acetate (0.01 mol) intoa 250 ml flask which is equipped with propeller and condensing unit,(2) after that, add then add 22.80 g of tetra-n-butyl titanate (0.067mol) and 46 g of ethanol (1 mol) into the flask, then conduct thereaction at a temperature of 80° C. for 2.5 hours,(3) remove small molecular products in the reaction system obtained instep (2) by dilution,(4) add 10.55 g of citric acid (0.050 mol), 3.12 g of tetraethoxysilane(0.015 mol) and 12.41 g of trimethyl phosphite (0.1 mol) into thereaction system in step (3) and conduct the reaction at a temperature ata temperature of 80° C. for 2.5 hours;(5) remove small molecular products in the reaction system obtained instep (4) by dilution and then catalyst in fluid state which contains3.42% of titanium by weight could be obtained.

The Eighth Embodiment

Consistent with this embodiment, the manufacturing method of thecatalyst used in the production of PBS or its copolyesters comprisessteps of:(1) add 31 g of ethanediol (0.5 mol) and 45.45 g of 1,4-butanediol (0.5mol) into a 250 ml flask which is equipped with propeller and condensingunit, then add 2.04 g of aluminium isopropoxide (0.01 mol) and 1.73 g ofcalcium acetate (0.0098 mol) into the flask,(2) after that, add 22.80 g of tetra-n-butyl titanate (0.067 mol) and 31g of ethanol (0.67 mol) into the flask, then conduct the reaction at atemperature of 80° C. for 2.5 hours,(3) remove small molecular products in the reaction system obtained instep (2) by dilution,(4) add 14.14 g of citric acid (0.067 mol), 13.96 g of tetraethoxysilane(0.067 mol) and 12.41 g of trimethyl phosphite (0.1 mol) into thereaction system in step (3) and conduct the reaction at a temperature ata temperature of 80° C. for 2.5 hours;(5) remove small molecular products in the reaction system obtained instep (4) by dilution and then catalyst in fluid state which contains2.34% of titanium by weight could be obtained.

The Ninth Embodiment

Consistent with this embodiment, the production of PBS using thecatalyst obtained in the previous embodiment comprises steps of:

-   -   mix 6 mol of succinic acid and 7.2 mol of 1,4-butanediol        together, then add 2.4 g of the catalyst obtained in the first        embodiment (the weight ratio of titanium atoms contained in the        catalyst and total weight of PBS or its copolyester is 123 ppm),        and then conduct the esterification reaction at a temperature of        230° C., then conduct the polycondensation after the        esterification reaction directly and the final polycondensation        is proceeded at a temperature of 240° C. and at a pressure of 35        Pa for 120 minutes, after that, PBS products are obtained. The        melt flow rate of the PBS product is 15 g/10 min and the “b”        value of the PBS product is 4.2.

The Tenth Embodiment

Consistent with this embodiment, the production of PBS using thecatalyst obtained in the previous embodiment comprises steps of:

-   -   mix 6 mol of succinic acid and 7.2 mol of 1,4-butanediol        together, then conduct the esterification reaction at a        temperature of 230˜240° C., after the water yield in the        esterification has reached 90% or more than 90% of the theoretic        result, add 3.6 g of the catalyst obtained in the second        embodiment (the weight ratio of titanium atoms contained in the        catalyst and total weight of PBS or its copolyester is 150 ppm),        then conduct the polycondensation and the final polycondensation        is proceeded at a temperature of 240° C. and at a pressure of 35        Pa for 120 minutes, after that, PBS products are obtained. The        melt flow rate of the PBS product is 6 g/10 min and the “b”        value of the PBS product is 7.0.

The Eleventh Embodiment

Consistent with this embodiment, the production process of PBS using thecatalyst obtained in the previous embodiment comprises almost the samesteps with the tenth embodiment, however, the catalyst added isdifferent. There are 2.5 g of the catalyst obtained in the thirdembodiment is added (the weight ratio of titanium atoms contained in thecatalyst and total weight of PBS or its copolyester is 100 ppm), afterthe final polycondensation which is proceeded for 140 minutes, PBSproducts are obtained. The melt flow rate of the PBS product is 16 g/10min and the “b” value of the PBS product is 5.6.

The Twelfth Embodiment

Consistent with this embodiment, the production process of PBS using thecatalyst obtained in the previous embodiment comprises almost the samesteps with the tenth embodiment, however, the catalyst added isdifferent. There are 7 g of the catalyst obtained in the fourthembodiment is added (the weight ratio of titanium atoms contained in thecatalyst and total weight of PBS or its copolyester is 140 ppm), afterthe final polycondensation which is proceeded for 105 minutes, PBSproducts are obtained. The melt flow rate of the PBS product is 20 g/10min and the “b” value of the PBS product is 4.5.

The Thirteenth Embodiment

Consistent with this embodiment, the production process of PBS using thecatalyst obtained in the previous embodiment comprises almost the samesteps with the ninth embodiment, however, the catalyst added isdifferent. There is 4 g of the catalyst obtained in the fifth embodimentis added (the weight ratio of titanium atoms contained in the catalystand total weight of PBS or its copolyester is 130 ppm), after the finalpolycondensation which is proceeded for 108 minutes, PBS products areobtained. The melt flow rate of the PBS product is 18 g/10 min and the“b” value of the PBS product is 4.9.

The Fourteenth Embodiment

Consistent with this embodiment, the production process of PBS using thecatalyst obtained in the previous embodiment comprises almost the samesteps with the tenth embodiment, however, the catalyst added isdifferent. There are 3 g of the catalyst obtained in the sixthembodiment is added (the weight ratio of titanium atoms contained in thecatalyst and total weight of PBS or its copolyester is 105 ppm), afterthe final polycondensation which is proceeded for 134 minutes, PBSproducts are obtained. The melt flow rate of the PBS product is 16 g/10min and the “b” value of the PBS product is 5.3.

The Fifteenth Embodiment

Consistent with this embodiment, the production process of PBS using thecatalyst obtained in the previous embodiment comprises almost the samesteps with the tenth embodiment. However, the catalyst added isdifferent. There are 3.5 g of the catalyst obtained in the seventhembodiment is added (the weight ratio of titanium atoms contained in thecatalyst and total weight of PBS or its copolyester is 120 ppm), afterthe final polycondensation which is proceeded for 125 minutes, PBSproducts are obtained. The melt flow rate of the PBS product is 19 g/10min and the “b” value of the PBS product is 3.9.

The Sixteenth Embodiment

Consistent with this embodiment, the production of PBS using thecatalyst obtained in the previous embodiment comprises steps of:

mix 5 mol of succinic acid, 1 mol of terephthalic acid, 6 mol of1,4-butanediol and 1.3 mol of ethanediol together, then conduct theesterification reaction at a temperature of 230˜250° C., after the wateryield in the esterification has reached 90% or more than 90% of thetheoretic result, add 6.4 g of the catalyst obtained in the eighthembodiment (the weight ratio of titanium atoms contained in the catalystand total weight of PBS or its copolyester is 150 ppm), then mix thereaction system and conduct the polycondensation and the finalpolycondensation is proceeded at a temperature of 275° C. and at apressure of 35 Pa for 140 minutes, after that, copolyester productscontaining PBS and polyethylene terephthalate(PET) are obtained. Themelt flow rate of the products is 8 g/10 min and the “b” value of thePBS product is 6.2.

Comparison Experiment

Consistent with this comparison experiment, the production process ofPBS using the catalyst obtained in the previous embodiment comprisesalmost the same steps with the tenth embodiment. However, the catalystadded is different. There is 4 g of tetrabutyl titanate is added (theweight ratio of titanium atoms contained in the catalyst and totalweight of PBS or its copolyester is 560 ppm), after the finalpolycondensation which is proceeded for 125 minutes, PBS products areobtained. The melt flow rate of the PBS product is 25g/10 min and the“b” value of the PBS product is 15.7.

The above description of the detailed embodiments are only to illustratethe preferred implementation according to the present invention, and itis not to limit the scope of the present invention, Accordingly, allmodifications and variations completed by those with ordinary skill inthe art should fall within the scope of present invention defined by theappended claims.

1. A manufacturing method of the catalyst used in the production of PBSor its copolyesters comprising steps of: (1) adding titanium alkoxide,silicon alkoxide, dihydric alcohol and metal co-catalyst into thesolvent and conducting the reaction at a temperature of about 80° C. to180° C., then removing the unreacted materials and small molecularproducts in the reaction system; (2) adding complexing agent into thereaction system obtained in step (1) and conducting the reaction at atemperature of about 80° C. to 180° C., then collecting catalyst fromthe products obtained in this step.
 2. The manufacturing method of thecatalyst used in the production of PBS or its copolyesters, as recitedin claim 1, wherein the reaction time in step (1) is ranging from 0.5hour to 2.5 hours and the reaction temperature in step (1) is rangingfrom 85° C. to 160° C.
 3. The manufacturing method of the catalyst usedin the production of PBS or its copolyesters, as recited in claim 1,wherein the reaction time in step (2) is ranging from 0.5 hour to 2.5hours and the reaction temperature in step (2) is ranging from 85° C. to160° C.
 4. A manufacturing method of the catalyst used in the productionof PBS or its copolyesters comprising steps of: (1) adding titaniumalkoxide, dihydric alcohol and metal co-catalyst into the solvent andconducting the reaction at a temperature of about 80° C. to 180° C.,then removing the unreacted materials and small molecular products inthe reaction system; (2) adding silicon alkoxide and complexing agentinto the reaction system obtained in step (1) and conducting thereaction at a temperature of about 80° C. to 180° C., then collectingcatalyst from the products obtained in this step.
 5. The manufacturingmethod of the catalyst used in the production of PBS or itscopolyesters, as recited in claim 4, wherein the reaction time in step(1) is ranging from 0.5 hour to 2.5 hours and the reaction temperaturein step (1) is ranging from 85° C. to 160° C.
 6. The manufacturingmethod of the catalyst used in the production of PBS or itscopolyesters, as recited in claim 4, wherein the reaction time in step(2) is ranging from 0.5 hour to 2.5 hours and the reaction temperaturein step (2) is ranging from 85° C. to 160° C.
 7. The manufacturingmethod of the catalyst used in the production of PBS or itscopolyesters, as recited in claim 1, wherein the titanium alkoxide isselected from the group comprising tetra-n-butyl titanate,tetra-isopropyl titanate and the mixture thereof, and the siliconalkoxide is selected from the group comprising methyl silicate, ethylsilicate and the mixture thereof.
 8. The manufacturing method of thecatalyst used in the production of PBS or its copolyesters, as recitedin claim 1, wherein the metal co-catalyst is selected from the groupcomprising acetates or alkoxides of Group IIA, IIIA, IIB or VIIIBmetals, or any mixture thereof; the dihydric alcohol is selected fromthe group comprising 1,4-butanediol, ethanediol, 1,3-propanediol,2-methyl-2,4-pentadiol, 1,5-pentanediol, 1,6-hexanediol and any mixturethereof; the solvent is selected from the group comprising ethanol,n-butanol, isopropanol and any mixture thereof; the complexing agentcomprises phosphate ester and hydroxyl carboxylic acid.
 9. Themanufacturing method of the catalyst used in the production of PBS orits copolyesters, as recited in claim 8, wherein the metal co-catalystis selected from the group comprising zinc acetate, aluminiumisopropoxide, calcium acetate, magnesium acetate, manganese acetate andany mixture thereof; the phosphate ester is selected from the groupcomprising trimethyl phosphate, trimethyl phosphite, triethyl phosphate,triethyl phosphite and any mixture thereof; the hydroxyl carboxylicacids is selected from the group comprising citric acid, tartaric acid,lactic acid and any mixture thereof; the molar ratio of titanium atomand dihydric alcohol is ranging from 1:5 to 1:30; the molar ratio oftitanium atom and metal co-catalyst is ranging from 1:0.05 to 1:2; themolar ratio of titanium atom and hydroxyl carboxylic acids is rangingfrom 1:0.5 to 1:2; the molar ratio of titanium atom and silicon atom isranging from 1:0.01 to 1:2; the molar ratio of titanium atom andphosphorus atoms is ranging from 1:0.01 to 1:2; the molar ratio oftitanium atom and solvent is ranging from 1:5 to 1:50.
 10. The catalystused in the production of PBS or its copolyesters obtained by the methodof claim
 1. 11. The manufacturing method of the catalyst used in theproduction of PBS or its copolyesters, as recited in claim 4, whereinthe titanium alkoxide is selected from the group comprisingtetra-n-butyl titanate, tetra-isopropyl titanate and the mixturethereof, and the silicon alkoxide is selected from the group comprisingmethyl silicate, ethyl silicate and the mixture thereof.
 12. Themanufacturing method of the catalyst used in the production of PBS orits copolyesters, as recited in claim 4, wherein the metal co-catalystis selected from the group comprising acetates or alkoxides of GroupIIA, IIIA, IIB or VIIIB metals, or any mixture thereof; the dihydricalcohol is selected from the group comprising 1,4-butanediol,ethanediol, 1,3-propanediol, 2-methyl-2,4-pentadiol, 1,5-pentanediol,1,6-hexanediol and any mixture thereof; the solvent is selected from thegroup comprising ethanol, n-butanol, isopropanol and any mixturethereof; the complexing agent comprises phosphate ester and hydroxylcarboxylic acid.
 13. The manufacturing method of the catalyst used inthe production of PBS or its copolyesters, as recited in claim 12,wherein the metal co-catalyst is selected from the group comprising zincacetate, aluminium isopropoxide, calcium acetate, magnesium acetate,manganese acetate and any mixture thereof; the phosphate ester isselected from the group comprising trimethyl phosphate, trimethylphosphite, triethyl phosphate, triethyl phosphite and any mixturethereof; the hydroxyl carboxylic acids is selected from the groupcomprising citric acid, tartaric acid, lactic acid and any mixturethereof; the molar ratio of titanium atom and dihydric alcohol isranging from 1:5 to 1:30; the molar ratio of titanium atom and metalco-catalyst is ranging from 1:0.05 to 1:2; the molar ratio of titaniumatom and hydroxyl carboxylic acids is ranging from 1:0.5 to 1:2; themolar ratio of titanium atom and silicon atom is ranging from 1:0.01 to1:2; the molar ratio of titanium atom and phosphorus atoms is rangingfrom 1:0.01 to 1:2; the molar ratio of titanium atom and solvent isranging from 1:5 to 1:50.
 14. The catalyst used in the production of PBSor its copolyesters obtained by the method of claim 4.